Steardimonium Hydroxypropyl Hydrolyzed Keratin

Steardimonium hydroxypropyl hydrolyzed keratin is a modified protein derived from keratin — the structural protein found naturally in hair and skin. The keratin is first broken down (hydrolysed) into smaller fragments, then chemically modified with stearic acid and a quaternary ammonium compound. This combination makes it soluble in cosmetic formulations and gives it conditioning properties.In skincare and haircare products, it functions primarily as a conditioning agent and antistatic. It deposits onto the surface of skin and hair to create a smoother feel and reduce frizz or static electr…

The hydrolyzed keratin fragments are small enough to deposit onto the outermost layers of skin. Once there, they form a light film that smooths the surface and can help reduce water loss temporarily. The quaternary ammonium modification gives the ingredient a slight positive charge, allowing it to bind more effectively to the skin's surface and reduce static build-up.This is a surface-level conditioning effect rather than a deeply penetrating one, meaning benefits are largely cosmetic and temporary.

This ingredient is typically used in leave-on products such as serums, creams and lotions at low concentrations. As it provides a temporary conditioning effect, consistent use will give the most noticeable results. It works well in combination with humectants and emollients that support the skin barrier.

Generally well-tolerated in cosmetic formulations. Those with atopic dermatitis or known sensitivity to protein derivatives should patch test first, as sensitisation to some protein hydrolysates has been documented in this population.